Field of the Disclosure
The present disclosure generally relates to a cable assembly having electrical power conductors and fiber optic data lines. Further on, the present disclosure generally relates to a power and communication system including such a cable assembly.
Technical Background
The present disclosure relates especially to FTTA (Fiber-To-The-Antenna) applications. Within an FTTA application, a power and communication system may include an antenna, where the antenna has a base station and a transmitter station. A cable assembly extends from the base station of the antenna to the transmitter station of the antenna, where the cable assembly includes electrical power conductors for providing electrical power from the base station to the or each transmitter station and includes fiber optic data lines for transmitting data signals between the base station to the transmitter station.
WO 2012/038104 A1 discloses a cable assembly having electrical power conductors and fiber optic data lines. This prior art cable assembly includes a hybrid cable having first electrical power conductors and first fiber optic data lines. This prior art cable assembly further comprises a plurality of electrical tether cables having second electrical power conductors and a fiber optic tether cable having second fiber optic data lines. In addition, this prior art cable assembly includes a joining location. The first electrical power conductors of the hybrid cable are connected with the second electrical power conductors of the electrical tether cable at the joining location. Further, first fiber optic data lines of the hybrid cable are connected with the second fiber optic data lines of the fiber optic tether cable at the joining location. According to WO 2012/038104 A1, the joining location is provided by a breakout enclosure in form of a box or a can.
In an FTTA application, the transmitter station of the antenna may be located on high structures, such as on top of a building or a tower. Due to this location, a risk of damage by a lightning strike is considerable. The cable assembly known from WO 2012/038104 A1 appears to be insufficiently protected against damage by a lightning strike.
The present patent application is based on the problem of providing a novel cable assembly and a novel power and communication system being sufficiently protected against damage by a lightning strike.
The furcation or joining location of the cable assembly comprises a shielding unit establishing an electrical contact between the shielding element of the hybrid cable and the shielding elements of the respective electrical tether cables, wherein the shielding unit comprises a central body made from an electrical conductive material surrounding the hybrid cable and tether cables in the region of the furcation or joining location, and wherein the central body is in electrical contact with the shielding element of the hybrid cable and with the shielding element of each electrical tether cable. Such a cable assembly is sufficiently protected against damage by a lightning strike. The shielding unit provides in longitudinal direction of the cable assembly a 360° shielding of all electrical power conductors and avoids an electrical overload on the power conductors due to lightning effects. The shielding unit protects the electrical power conductors against an electromagnetic impulse and transmits a lightning current to ground.
Preferably, the shielding unit further comprises a first nut-like body made from an electrical conductive material being fastenable to a first end of the central body in the region of the hybrid cable providing an electrical contact with the shielding element of the hybrid cable, and a second nut-like body made from an electrical conductive material being fastenable to a second end of the central body in the region of the tether cable providing an electrical contact with the shielding element of each electrical tether cable. This modular design of the shielding unit allows the adaption of the shielding unit and thereby of the cable assembly to different cable diameters of the hybrid cable and/or to different numbers of tether cables.
According to an improved embodiment, the shielding unit further comprises a first compression element made from an electrical conductive material being positioned between first nut-like body and the hybrid cable, wherein the first compression element becomes compressed when the first nut-like body becomes fastened to the central body such that the compressed first compression element provides an electrical conductive path between the shielding element of the hybrid cable and the central body. This improves the electrical connection of the shielding unit with the shielding element of the hybrid cable and improves protection against damage by a lightning strike.
According to a further improved embodiment, the shielding unit further comprises a second compression element made from an electrical conductive material being positioned between second nut-like body and the tether cables, wherein the second compression element becomes compressed when the second nut-like body becomes fastened to the central body such that the compressed second compression element provides an electrical conductive path between the shielding elements of the electrical tether cables and the central body. This improves the electrical connection of the shielding unit with the shielding element of each electrical tether cable and further improves protection against damage by a lightning strike.
According to a further improved embodiment, the shielding unit further comprises a separator element made from an electrical conductive material, wherein the separator element comprises recesses for receiving the electrical tether cables, and wherein the electrical tether cables become pressed into the recesses of the separator element when the second compression element becomes compressed, thereby providing an electrical conductive path on the one hand between the shielding elements of the electrical tether cables and the central body, and on the other hand between the shielding elements of the electrical tether cables and the separator element. The separator element ensures that the shielding elements of the power tether cables are kept in the right position, thereby further improving the electrical connection of the shielding unit with the shielding elements of the electrical tether cables and thereby further improving the protection against damage by a lightning strike.
Preferably, the separator element of the shielding unit comprises an opening for receiving and contacting a grounding wire. This further improves protection against damage by a lightning strike.
Preferably, the shielding unit is filled with an insulation material. The insulation material further improves protection against damage by a lightning strike and provides strain relief for the hybrid cable and tether cables.
Preferably, the shielding unit is over-molded. The over-mold seals the hole joining point against environmental influences like water and dust